"On job" is another way to describe someone who is currently working or performing their job duties. There are a variety of synonyms that can be used to describe this state, such as "working," "employed," "occupied," "engaged," "tasked," "busy," "active," "at work," and "on duty." Each of these synonyms paint a slightly different picture of the state of being focused on work-related tasks. For example, "busy" connotes a high volume of tasks, while "on duty" suggests a sense of responsibility and obligation. Regardless of the specific synonym used, they all describe someone who is currently engaged in their job and actively pursuing their work goals.